Lateral Wall of the Cavum Nasi in Man. 



697 



In fig, 50 anterior ethmoidal cells from two frontal furrows are 

 developed sufficiently to be called frontal sinuses. Both communi- 

 cate with the frontal recess or the ventral and superiot portion of 

 the meatus medius. In such instances the intervening wall may 

 break down and an adult frontal sinus with two nasofrontal ducts 

 will be present. Occasionally we find a frontal sinus with two 



Dnctus nasofrontalis 

 Inftmdibuhm ethmoidale^ 

 Bulla ethmoldalis 



-Sinus frontalis 



Processus 

 uncinafus 



Ostium maxiUare 

 accessorium 



Fig. 49 A semidiagrammatic drawing of an adult lateral nasal wall. The 

 concha nasalis media is partly cut away. The infundibulum ethmoidale is directly 

 continuous with the nasofrontal duct — a condition not common. 



ducts leading from it, and the above explanation for such a con- 

 dition seems plausible. 



If we take all the cases that fall under the types as represented 

 by figs. 47 and 49, they will include about 56 per cent of my speci- 

 mens, type, fig. 47, being much the more common of the two. In a 

 previous paper these two types were included among the specimens 

 as representing positive fronto-maxillary relations. The speci- 

 mens falling under the type as represented by fig. 46 will also 

 frequently fall under the above classification. The specimens 



JOURNAu OF MOBPHOLOGY, VOL. 21, NO. 4. 



